harmony 鸿蒙Media Development

2022-12-13
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Media Development

How do I set a front camera?

Applicable to: OpenHarmony SDK 3.2.3.5, stage model of API version 9

Set the camera position to camera.CameraPosition.CAMERA_POSITION_FRONT.
Create a CameraInput instance based on the camera position and type.

Example:

// The rear camera is set by default. You can use **isFrontCamera** to switch to the rear camera.
let cameraId
let cameraInput
for(let cameraIndex = 0; cameraIndex < this.cameraArray.length; cameraIndex++) {
   let faceType = this.cameraArray[cameraIndex].cameraPosition
   switch(faceType) {
  case camera.CameraPosition.CAMERA_POSITION_FRONT: // Front camera
    if(this.isFrontCamera){
   cameraId = this.cameraArray[cameraIndex].cameraId
    }
	   break
	 case camera.CameraPosition.CAMERA_POSITION_BACK: // Rear camera
	   if(!this.isFrontCamera){
		 cameraId = this.cameraArray[cameraIndex].cameraId
	   }
	   break
	 case camera.CameraPosition.CAMERA_POSITION_UNSPECIFIED:
	 default:
	   break
   }
}
cameraInput = await this.cameraManager.createCameraInput(cameraId)

How do I crop an image?

Applicable to: OpenHarmony SDK 3.2.5.6, stage model of API version 9

Create an ImageSource instance based on the input URI.

   let path = this.context.getApplicationContext().fileDirs + "test.jpg";
   const imageSourceApi = image.createImageSource(path);

Set decoding parameters and decode the image to obtain a PixelMap object. Image processing is supported during decoding.
- Set desiredSize to specify the target size after scaling. If the values are all set to 0, scaling will not be performed.
- Set desiredRegion to specify the target rectangular area after cropping. If the values are all set to 0, cropping will not be performed.
- Set rotateDegrees to specify the rotation angle. The image will be rotated clockwise at the center.
```
  const decodingOptions = {
    desiredSize: {
    height:0,
    width:0
    },
    // Crop a rectangular area.
    desiredRegion: {
    size: {
     height:100,
     width:100
    },
    x:0,
    y:0
    },
    // Rotate the image by 90 degrees.
    rotate:90
  }
  imageSourceApi.createPixelMap(decodingOptions).then(pixelMap => {
    this.handlePixelMap(pixelMap)
  })
```
Process the obtained PixelMap object. For example, render and display the image.

How do I apply for the media read/write permission on a device?

Applicable to: OpenHarmony SDK 3.2.5.5, stage model of API version 9

Configure the permissions ohos.permission.READ_MEDIA and ohos.permission.WRITE_MEDIA in the module.json5 file. Example:

   {
     "module" : {
       "requestPermissions":[
         {
           "name" : "ohos.permission.READ_MEDIA",
           "reason": "$string:reason"
         },
         {
           "name" : "ohos.permission.WRITE_MEDIA",
           "reason": "$string:reason"
         }
       ]
     }
   }

Call requestPermissionsFromUser to request the permissions from end users in the form of a dialog box. This operation is required because the grant mode of both permissions is user_grant.

   import abilityAccessCtrl from '@ohos.abilityAccessCtrl.d.ts';
   
   let permissions: Array<string> = ['ohos.permission.READ_MEDIA','ohos.permission.WRITE_MEDIA']
   let atManager = abilityAccessCtrl.createAtManager();
   // context is the ability-level context of the initiator UIAbility.
   atManager.requestPermissionsFromUser(context, permissions).then((data) => {
       console.log("Succeed to request permission from user with data: " + JSON.stringify(data))
   }).catch((error) => {
       console.log("Failed to request permission from user with error: " + JSON.stringify(error))
   })